Afghanistan briefly flirted with the possibility of another huge upset in the World Cup before poor fielding allowed New Zealand to post a commanding total in Chennai and seal a comfortable 149-run win on Wednesday.
All the hard work put in by Afghanistan's bowlers on a helpful MA Chidambaram Stadium surface was undone by the fielders as they dropped five chances. New Zealand's batsmen did not need a second invitation as they made 288-6, which proved well beyond Afghanistan's reach.
Under lights, New Zealand's bowlers were ruthless, getting the ball to move and turn prodigiously to bundle out Afghanistan for just 139 and seal victory with more than 15 overs to spare.
For the Kiwis, left-arm spinner Mitchell Santner (3-29) and pacer Lockie Ferguson (3-19) cleaned up the lower order while Trent Boult picked up 2-18.
Earlier, captain Tom Latham (68) and Glenn Phillips (71) hit half-centuries while opener Will Young scored a sedate fifty.
The Black Caps were helped by sloppy Afghan fielders, who dropped four catches and also messed up a stumping opportunity.
The slide started in the second over when Rahmat Shah dropped Young at first slip. Even though Afghanistan fought back with three wickets in the 21st and 22nd overs, New Zealand plugged away.
From 110-4, New Zealand pulled away with a century stand between Latham and Phillips. Phillips was the top scorer with 71 off 80 balls and put on 144 runs for the fifth wicket with his captain.
In reply, not a single Afghanistan batsman reached fifty, with Shah top-scoring with 36 against a disciplined Kiwi attack.
New Zealand thus climbed to the top of the table with their fourth victory of the tournament. They are in first place on a maximum eight points, with India – with three straight victories – the only other unbeaten team.
Afghanistan captain Hashmatullah Shahidi admitted his team's fielding cost them the match.
"Very disappointed because at this level you have to take those kind of catches. The team was doing well but the fielding made us feel a little bit down. Last six overs, a lot of runs were made by New Zealand," Shahidi said.
"We dropped two catches before 40th over and the set batters were there. That's why we couldn't stop them and everything went their way."
New Zealand captain Latham was pleased with the way his team fought back after losing three wickets in two overs in the middle.
"Pleasing start, another great performance. We were put under pressure at certain times but putting pressure back on them at end of the innings was great," he said.